The rivers around the capital in particular are polluted due to mindless
dumping of untreated waste and effluents that contain heavy metals and residues
of toxic chemical, they observe.

“As a natural resource, sweet water is as valuable as minerals like coal and
natural gas,” Hasin Jahan, policy advocacy director of WaterAid Bangladesh,
told The Daily Star.

“The rivers, the prime sources of sweet water, are being contaminated
heavily with lethal effluents,” she observed.

Besides, rainwater, the purest form of natural water, is callously wasted by
letting it run off and merge with polluted rivers in the absence of a
harvesting system, she said.

Of the 80,000 tonnes of human waste generated a day in the country, at best
two percent (1,600 tonnes) is treated at Pagla treatment plant near the
capital, and the rest eventually ends up in rivers, said Hasin.

Most industries in and around the capital release untreated effluents
directly into the Buriganga, Shitalakhya, Balu and Turag rivers, taking
advantage of the authorities' lax attitude towards enforcing environmental laws
and regulations, she added.

Prof Mujibur Rahman of Bangladesh University of Engineering and Technology
said river water is turning unsafe for drinking because of rampant release of
untreated human waste and industrial effluents that contain heavy metals like
chromium, cadmium, lead and mercury, and toxic chemicals.

More than 300 rivers in Bangladesh are polluted the same way, said Mujibur,
who has worked extensively on environmental issues.

Such pollution makes river waters unsuitable for agriculture, fishing,
household chores, and bathing. It also ruins the riverine ecological system and
biodiversity.

The four rivers around the capital have become virtual dumping grounds for
all kinds of solid, liquid and chemical waste, as hundreds of tanneries and
textile factories are situated by these water bodies, he observed.

Prof Dr Mohammad Ali, who has carried out the first liver transplant in the
country, said excessive accumulation of heavy metals through regular
consumption of contaminated food and water might damage brain, liver, kidney and
the nerves.

Contaminated water could cause deadly hepatitis-A and E and typhoid, and
eventually lead to liver failure, particularly in children and pregnant women,
said Prof Ali, also founder secretary general of National Liver Foundation of
Bangladesh.

According to the findings of WaterAid Bangladesh, more than 7,000 children
under five die from diarrhoea while waterborne diseases cause nearly a quarter
of total deaths a year in the country.

Taqsem A Khan, managing director of Dhaka Water Supply and Sewerage
Authority (Wasa), said, “Unfortunately, the rivers around Dhaka are so polluted
that their water is almost impossible to treat.”

Dhaka Wasa, which serves around 12.5 million people in a
360-square-kilometre area, uses water of only the Shitalakkhya at a
pre-treatment and treatment plants at Sayedabad to meet 22 percent of the total
demand for 230 crore litres of water. The rest is extracted from underground.

The groundwater table in Dhaka city depletes by around three metres a year
with roughly 1.5 metres of annual recharge, according to an official estimate.

Taqsem said replenishment of the groundwater table is obstructed due to
unplanned concrete coverage of the surface, and destruction of wetlands, open
space and rivers.

Rainwater, which is supposed to recharge the water table, runs off the
concrete surface and merge with polluted water of rivers.

Mega projects, including Jasaldia (Mawa) and Gandhabpur (Narayanganj) water
treatment plants, have been taken up to bring water from the Padma and the
Meghna, from a distance of 33 km and 23 km to supply surface water to the city
dwellers, said the Wasa boss.

He said only 20 percent of the population whom the Wasa serves is under
sewer coverage.

Those beyond the coverage don't have septic tanks and release human waste
directly into the environment through open and storm drains as well as rivers,
he added.